This invention relates generally to dispensing devices, and more specifically to dispensing devices for high viscosity compositions, such as caulking materials, grease, automotive windshield sealant, dual component reactive resins, and the like.
Dispensing devices for high viscosity compositions are well known in the art and employ a variety of dispensing drive systems.
A number of patents disclose drive systems wherein a trigger includes a drive dog as an integral part thereof, or includes a drive member directly connected thereto, for directly engaging and actuating a driving grip through which a drive rod extends. Representative patents disclosing these types of arrangements are U.S. Pat. Nos. 5,197,635 (Chang); 4,681,524 (Ikeda, et al.); 4,509,662 (Weiss); 4,461,407 (Finnegan); 4,081,112 (Chang); 4,009,804 (Costa, et al.); 2,731,176 (Crewe) and 1,231,733 (Arden).
U.S. Pat. No. 4,641,766, issued to Vlasich, discloses an arrangement for dispensing high viscosity compositions, wherein a piston 16 is slidable within a chamber 14 containing the composition to be dispensed, and a plunger rod 18 connected to the piston has spaced disc-shaped projections thereon. The spaces between the projections are engaged by diametrically opposed teeth 27 forming part of diametrically opposed, manually actuatable arms 25a and 25b for feeding the piston 16 in a composition-dispensing direction.
U.S. Pat. No. 3,029,653, issued to Nilsson, discloses a dispensing device in which either a downwardly extending dog 29 or an upwardly extending dog 30 is employed to engage with rachet teeth 31 of a piston rod 18 and thereby move the piston rod for dispensing a caulking composition. To effect movement of the piston rod 18 a link member 23 is rotatably secured at one end to a manually actuatable trigger 26 by a pivot pin 25, and at its opposite end to a lower end of an operating lever 21 carrying the dogs 29 and 30. The operating lever 21 is pivotally mounted adjacent an upper end thereof to a pivot pin 22, and is pivotally joined to the link member 23 through a pivot pin 24. As is best seen in FIG. 4, it appears that the angular orientation between the link member 23 and the operating lever 21 remains substantially the same both prior to and after actuation of the trigger 26 to cause either the upper dog 29 or the lower dog 30 to cooperate with rachet teeth 31 in feeding the piston rod 18 in a composition-dispensing direction.
U.S. Pat. No. 2,138,045, issued to Seeberger, discloses a rachet driving mechanism for a driving rod 11 employing a fairly complex arrangement of links for operating a power-applying member 12 for moving the piston rod 11. Specifically, the power-applying member 12 is operatively connected to a trigger lever 13 by a toggle mechanism including the several links 14, 15 and 16; with one end of the link 14 being pivotally connected at 14a to the trigger lever 13 and the opposite end of said link being connected at 14b to the links 15 and 16. In addition to the fairly complex linkage system employed for driving the rod 11, the Seeberger system also includes a fairly complex arrangement for preventing undesired retraction of the rod 11. This arrangement includes a detent 18 slidably mounted in cam members 20 which, in turn, are manually controlled by the operation of a lever 25.
U.S. Pat. No. 4,566,610, issued to Herb, discloses an exemplary embodiment of a hand-held dispensing device for multi-component guns. In this latter device a pair of piston rods 8 and 9 are positively driven by a driving device 14 that is pulled forwardly by a link 13 interconnected to the driving device 14 and to a hand-operated lever 10.
The prior art devices, while generally usable for their intended purpose, either do not provide a sufficiently high thrust for permitting easy dispensing of very high viscosity compositions, and/or are undesirably complex in construction.